Before I run out and buy a new rear tire I wonder if someone could give an opinion on the condition of this Conti Blitz. It's pretty old and the bike had a sidecar on it for most of the tire's life, which is probably why it's worn in the center region. Plus I do most of my riding on highways for utility not a whole lot on on twisties for pleasure.

I've never been schooled on the ins and outs of MC tire wear -- don't even know what the dimples are for -- I assume they're to help assess how much rubber is left. As replacement I'm looking at a Shinko 712 which is what I have on the front. The front looks pretty new. You'd think I'd remember more about the wheres and whens of my tire purchasing but the time period in which these tires were installed is a blur and preceded the birth of motobrick.com. So if there's some formula or measurement for determining when to replace, I'd appreciate your input.
BTW no car tior available for 130/90 17 and not doing any wheel mods -- nuff said 'bout that.
Thanks -- Van